1. Field of the Invention
The present invention relates to a semiconductor chip and a method of obtaining the same and, more specifically, it relates to improvement for preventing a semiconductor chip from cracking to the inside of a electronic element region in the semiconductor chip in cutting a semiconductor wafer into semiconductor chips by dicing.
2. DESCRIPTION OF THE PRIOR ART
As well-known in the field of manufacturing a semiconductor device, a semiconductor wafer in which an array of electronic element regions are fabricated is subjected to a dicing process so that the semiconductor wafer is cut into a plurality of semiconductor chips each of which has an electronic element region. FIG. 6A is a partial sectional view showing a semiconductor wafer in which an array of electronic element regions 20 is fabricated on one of a major surfaces of a semiconductor substrate 1, and this figure corresponds to a sectional view taken along line 6A--6A of FIG. 7A which is a partial plan view of the semiconductor wafer. Each of the electronic element regions 20 includes an active region 2 having at least one electronic element and a silicon oxide film 4 covering the active region 2. The word "active region" is herein used as a general term for a construction related to the operation of the electronic element, and it may includes a pn junction construction, a MOS construction and/or other various constructions. In the drawings, without discriminating between these elements, they are represented as the active region 2.
A silicon nitride film 10 is formed as a passivation film on the top surface of each of the silicon oxide films 4. Further, an isolating zone or a dicing line (street line) 5 is provided between adjacent silicon oxide films 4 to isolate the electronic element regions 20 from each other and define a space for dicing.
As illustrated in a partial plan view of FIG. 7B showing the semiconductor wafer and in a sectional view of FIG. 6B taken along line 6B--6B of FIG. 7B, the dicing process inCludes a step of forming a cutting groove 14 along the dicing line 5 in the semiconductor substrate 1. The semiconductor wafer is then cut into a plurality of semiconductor chips at the groove 5 such that the electronic element regions 20 ar assigned to the plurality of chips, respectively.
As methods of attaining such a dicing, a mechanical dicing method using a rotational blade or a diamond scriber and a non-mechanical dicing method using a laser scriber or the like are known. Especially, in the mechanical dicing method, since mechanical vibration and cutting stress are applied to the semiconductor wafer, a crack 50 extending from the cutting groove 14 to the electronic element region 20 is often caused in the semiconductor substrate 1. If the crack 50 reaches the active region 2, the semiconductor chip might be thrown away as a defective chip. As a result, the yield in the dicing process can hardly be improved, which leads to increase in cost of the semiconductor chips and accordingly in cost of the resultant semiconductor devices having the semiconductor chips. The crack may also detract from the reliability of the semiconductor device.